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Best 18 TB Hard Drives

18 TB is a popular capacity sweet spot for NAS builders, homelab enthusiasts, and small-business storage. It offers strong density per bay slot without the price premium of cutting-edge 20-24 TB models. At this capacity point, you will find mature, well-proven models from both Seagate and Western Digital across enterprise, NAS, and general-purpose lines.

Why 18 TB?

18 TB drives hit a practical balance: enough capacity to meaningfully reduce the number of bays needed, but typically priced lower per TB than 20 TB+ models because they use established platter technology. For a 4-bay NAS, four 18 TB drives give you 72 TB raw — or ~54 TB usable in RAID 5.

Prices updated hourly from Amazon US and UK. All links go directly to the retailer. Details.

Best Value 18 TB Drives

All new 18 TB hard drives ranked by price per terabyte. The best deals across enterprise, NAS, and standard lines.

£16.95/TB New

WD Elements 18TB Desktop USB 3.0 External Hard Drive with the SanDisk Ultra 256GB USB 3.0 Flash Drive

18 TB External 3.5" USB
£305.17 Amazon UK· 3h
$18.89/TB New

MDD MAXDIGITALDATA MDD 18TB 7200RPM 256MB Cache SAS 12.0Gb/s 3.5inch Internal Enterprise Hard Drive (MDD18TSAS25672E) - [Not a SATA HDD]

18 TB Internal 3.5" SAS
$339.99 Amazon US· 1h 13m
£19.06/TB New

WD 18TB Elements Desktop External Hard Drive - USB 3.0, Black

18 TB External 3.5" USB
£343.00 Amazon UK· 3h 1m
$21.67/TB New

Western Digital 18TB Elements Desktop External Hard Drive USB 3.0 for plug-and-play storage - Western DigitalBWLG0180HBK-NESN

18 TB External 3.5" USB
$389.99 Amazon US· 2h 39m
$22.22/TB New

Avolusion PRO-G2 18TB USB 3.2 Gen 2 (10Gbps) External Hard Drive for Windows/MacOS (Silver)

18 TB External 3.5" USB
$399.99 Amazon US· 22h 13m
$22.22/TB New

MDD (MDD18TSATA25672DVR) 18TB 7200RPM 256MB Cache SATA 6.0Gb/s 3.5inch Internal Surveillance Hard Drive - 3 Years Warranty

18 TB Internal 3.5" SATA
$399.99 Amazon US· 1h 14m
$22.78/TB New

Western Digital Internal Hard Drives 18Tb DC HC550 Surveillance,Wd 3.5 HDD Sata 6Gb/s 7200 PRM NAS 512 mb Cache for Dvr Nvr

18 TB Internal 3.5" SATA
$409.99 Amazon US· 1d 18h
£24.83/TB New

WD Red Pro 18TB NAS 3.5" Internal Hard Drive - 7200 RPM Class, SATA 6 Gb/s, CMR Recording Technology, 512MB Cache

18 TB Internal 3.5" SATA
£447.00 Amazon UK· 1h 58m

Enterprise 18 TB Drives

Seagate Exos and WD Ultrastar 18 TB models for server and datacenter use. 24/7 rated with 5-year warranties and high workload endurance.

£27.19/TB New

Seagate Exos X18 Enterprise Class, 18TB, Enterprise Internal Hard Drive, SATA, 3,5" 6Gbit/s, 128MB cache ((ST18000NM000J)

18 TB Internal 3.5" SATA
£489.40 Amazon UK· 1h
$29.52/TB New

Western Digital Ultrastar DC HC550 18 TB Hard Drive - 3.5 Internal - SATA

18 TB Internal 3.5" SATA
$531.45 Amazon US· 2h 44m
$30.55/TB New

Western Digital Ultrastar DC HC550 18 TB Hard Drive - 3.5" Internal - SATA

18 TB Internal 3.5" SATA
$549.99 Amazon US· 2h 24m
£34.33/TB New

Western Digital Ultrastar DC HC550 Enterprise Hard Drive 18TB (3.5" SATA 6Gbps, SAS 12Gbps, 7200RPM, 512MB Cache)

18 TB Internal 3.5" SATA
£618.00 Amazon UK· 4h
£35.56/TB New

Seagate Exos X20 18TB Internal Hard Drive - 3.5 Inch Hyperscale 12GB/s SAS HDD, 7,200 RPM, 2.5M MTBF, 512e and 4Kn FastFormat, Low Latency with Enhanced Caching (ST18000NM000D)

18 TB Internal 2.5" SAS
£640.00 Amazon UK· 16m
$37.50/TB New

Seagate ST18000NM003D 18TB Exos X20 SATA Hard Drive, 3.5" HDD, SATA 6Gb/s, 7200rpm, 256MB Cache, 512E, 4.16ms, NCQ

18 TB Internal 3.5" SATA
$675.00 Amazon US· 2h 18m
$38.86/TB New

Seagate Exos X18 ST18000NM001J 18 TB Hard Drive - Internal - SATA (SATA/600)

18 TB Internal 3.5" SATA
$699.45 Amazon US· 2h 22m
$38.88/TB New

Seagate Exos X18 ST18000NM005J 18 TB Hard Drive - Internal - SAS (12Gb/s SAS) - 7200rpm - 5 Year Warranty

18 TB Internal 3.5" SAS
$699.75 Amazon US· 2h 25m

NAS 18 TB Drives

IronWolf and WD Red 18 TB models designed for always-on NAS enclosures. NAS firmware optimisations for RAID and multi-bay vibration.

£24.83/TB New

WD Red Pro 18TB NAS 3.5" Internal Hard Drive - 7200 RPM Class, SATA 6 Gb/s, CMR Recording Technology, 512MB Cache

18 TB Internal 3.5" SATA
£447.00 Amazon UK· 1h 58m

Refurbished 18 TB Drives

Used and recertified 18 TB drives at reduced prices. Enterprise datacenter pulls that offer strong value for non-critical storage and homelab use.

$16.67/TB Used

MDD MAXDIGITALDATA X18 MACH.2 (Dual Actuator) 18TB 7200RPM SAS 12Gb/s 512MB Cache 3.5-Inch Enterprise Hard Drive (MDD18TSAS51272E-2X18) - [Not a SATA HDD] (Renewed)

18 TB Internal 3.5" SAS
$299.99 Amazon US· 5h 46m
£17.34/TB Used

WD 18TB Elements Desktop External Hard Drive - USB 3.0, Black

18 TB External 3.5" USB
£312.13 Amazon UK· 3h 1m
£17.72/TB Used

Western Digital HDD Gold 18 TB SATA 512 MB 3.5 Inch

18 TB Internal 3.5" SATA
£319.00 Amazon UK· 16m
$17.78/TB Used

MDD MAXDIGITALDATA MDD 18TB 7200RPM 256MB Cache SAS 12.0Gb/s 3.5inch Internal Enterprise Hard Drive (MDD18TSAS25672E) - [Not a SATA HDD] (Renewed)

18 TB Internal 3.5" SAS
$319.99 Amazon US· 17h 54m
$20.31/TB Used

Water Panther 18TB SAS 12Gb/s 7.2K RPM 3.5-Inch Enterprise Hard Disk Drive in 14G 15G Tray Compatible with Dell PowerEdge Servers R240 R340 R740XD R550 R750 (Renewed)

18 TB Internal 3.5" SAS
$365.55 Amazon US· 2h 15m
$20.31/TB Used

Water Panther 18TB 7200 RPM SAS 12Gb/s 3.5-Inch Enterprise Hard Disk Drive in 13G Tray Compatible with Dell PowerEdge Servers R730XD R730 T340 T330 T640 T630 T440 (Renewed)

18 TB Internal 3.5" SAS
$365.55 Amazon US· 4h 5m
$20.31/TB Used

Seagate Enterprise ST18000NM004J Internal Hard Drive 3.5" 18TB 7.2K RPM SAS 12Gb/s for Servers *Desktop PC's Not Supported*(Renewed)

18 TB Internal 3.5" SAS
$365.55 Amazon US· 5h 46m
$20.31/TB Used

Water Panther WP Arsenal 18TB SAS 12Gb/s 7200RPM 3.5-Inch DAS Hard Drive for Storage Server, Enterprise JBOD, Business RAID Workstation, Internal SAS LFF HDD (Renewed)

18 TB Internal 3.5" SAS
$365.55 Amazon US· 3h 20m